The National Institute of Environmental Health Sciences is currently the major Federal agency supporting training for research careers in environmental epidemiology and in the process, the development of a document describing the important facets of an environmental epidemiology training program. Whereas extant programs are situated in universities with both environmental and nonenvironmental epidemiology training, the Institute requires a determination of how its support stimulates the development of the environmental field and how the training of epidemiologists in thisfield differs from those in classical training. In addition, the job market for individuals so trained must be so defined in all sectors of the economy (academic, industrial, and governmental).